1. Field of the Invention
This invention relates to the field of therapeutic pools and more particularly to air supply systems for such pools.
2. Description of the Prior Art
A therapeutic pool, or spa, is comprised of a waterfilled tub large enough to accommodate the desired number of people neck deep and includes means for introducing air into the water through numerous orifices in the floor of the tub so that a large number of bubbles are formed and a pleasant sensation is created upon the body as they rise to the surface of the tub. Certain therapeutic benefits such as improved blood circulation are said to accrue from allowing bubbles to play on the surface of the skin and gently message it.
It is common to use a blower or pump to generate air pressure which is piped to a chamber under the tube and thence into the tube through a plurality of orifices in the tube bottom. Since water will flow back through the air supply piping when the blower is inoperative, the blower is normally positioned above the water line to prevent its being damaged by water backflow from the tube. It is desirable for esthetic reasons, however, to locate the blower below the water level, but in order to do so some means must be used to prevent water from backing up into the blower when the blower is off.
Prior to the present invention no satisfactory means for preventing such backflow had been devised. Common check valves have been tried, but they invariably leak with resultant damage to the blower. Successful prior art spas therefore position the pumping means above the water surface, even though a more desirable position would be below the water level.
It is therefore an object of the present invention to provide a piping and valving system for a therapeutic pool which is economical and efficient and which will protect the system blower from water backflow even though the blower is positioned at a level below the water surface.